Monarflex Moisture and vapour barriers
What is a vapour control layer?
A vapour control layer is a vapour tight membrane that is installed on the warm side of the roof or on the exterior house wall. If a vapour control layer is installed in a wall, it must be a light construction, meaning that the inside wall of the house is made from wood, gypsum or similar light weight building materials for walls.
The function of a vapour control layer is to avoid that the moisture which is build up inside a house, will find its way to the insulation material, which then will absorb the moisture, making the insulation material lose its ability to insulate.
Why use a vapour control layer?
Not many are aware of why the vapour control layer (VCL) is so essential, but consider what happens when warm and cold air meets, and what will this mean for the building physics in winter and summer cli-mate. When warm air meets a cold surface condensation will occur and consequently water/moisture will start forming.
The following factors may lead to problems with moisture/vapour in a construction:
• Vapour from indoor climate
• Building moisture in construction materials
• Ground moisture
The main reason for problems with moisture in buildings is vapour that comes from the indoor climate, meaning vapour that forms from the habitat area. Water vapour occurs when warm air with high humidity meets a colder surface, where moisture can form. To give an example of this, the best would be a cold glass on a hot summer day, where huge amounts of moisture will form on the outside surface of the glass.
To further understand the importance of having a VCL we can look at the indoor air. The indoor air needs to absorb the moisture that builds up in a standard house with 2 adults and 2 children living under normal conditions which can be as much as 10 litres of water per 24 hours. All this water vapour naturally needs to go somewhere, and since it cannot all be ventilated out by opening a window, a need for a VCL is obvi-ous. Without the VCL this water vapour would go into the insulation material as well as the wooden con-struction.
Product range
The Monarflex product portfolio for vapour control layers covers all the needs for different applications ranging from ordinary houses with regular levels of water vapour to the swimming halls with extreme water vapour.
The vapour control layers from the Monarflex portfolio is one of the widest on the market as it covers all three categories for vapour loads:
• Low loads – Ordinary houses
• Medium loads – Ordinary houses and industrial buildings
• High loads – Industrial buildings and swimming, sports halls
The products that are designed to withstand low water vapour load is made from pure polyethylene with or without a reinforcing grid with a thickness of minimum 200 micron.
Products that are in the medium water vapour load area is made from polyethylene of minimum 250 mi-cron and always reinforced to prevent tearing during the crucial installation. Further products are made from metalized film and polyethylene with a reinforcing grid of polyester.
All the vapour control layers from Monarflex that are design to handle extreme high loads of water vapour all incorporate a pure sheet of aluminium to make sure that vapour cannot penetrate the protective VCL.
All the materials used to produce the Monarflex vapour control layers are from virgin material, hence no recycled material is used.
Monarflex current vapour control barrier portfolio is:
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Low water vapour load
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• MONARFLEX® Elephant Skin
• MONARFLEX® Netofol 200 VB |
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Medium water vapour load
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• MONARFLEX® Monofilament 250
• MONARFLEX® Monofilament 250 FR
• MONARFLEX® Pam-O-Flex
• ICOPAL® MonarVap Reflex |
High water vapour load |
• MONARFLEX® Polykraft STD
• MONARFLEX® Polykraft RE
• MONARFLEX® Reflex V-TEK
• MONARFLEX® Reflex 275 |
Foundation – moisture membrane |
| • MONARFLEX® DPC |
Choose the right product
When having to choose the right product for the job, it is very important to remember that the vapour con-trol layer has the same function as a roof underlay, it is just installed on the warm side (the side that turns inwards towards the habitat area) of the insulation material for protection of the insulation material from moisture coming from use of the habitat area.
The following conditions most be evaluated before choosing the product:
• What kind of moisture load can be expected – high, medium or low
• Should the product be used in walls, roof or floor
o Monarflex product used in walls:
- All our VCL products
o Monarflex products used in roofs
- All our VCL products
o Monarflex products used in floors
- MONARFLEX® Elephant Skin
- MONARFLEX® Monofilament 250
- MONARFLEX® Reflex 275
o Monarflex product used as foundation moisture barrier
- MONARFLEX® DPC
• If the membrane is installed close to a heating source like a radiator, this should be considered, as heat will over long time have a degrading effect on the VCL and therefore ageing properties is cru-cial.
Trend
It has become a trend to have reflective vapour control layers in order to reduce the heat loss from build-ing during winter time. Monarflex has of course followed this trend and thus have products like MONAR-FLEX® Polykraft and ICOPAL® MonarVap Reflex in our VCL portfolio. An important thing to remember with the reflective membranes is that you can only reflect the IR (inferred heat), which approximately half of the heat is coming from a heated room.
Importance of application
In order to get the optimal protection out of the Monarflex vapour control layer it is extremely important to recognize that the installation and the role that the accessories play is just as important as the vapour control layers itself. By using the different Monarflex tape accessories a total system is formed, which will as-sist the vapour control layer in being the best possible protection for the insulation material.
At Monarflex "we are setting the standard"